1. Field of the Invention
The present invention relates to a biological microparticle inspection apparatus for selectively counting specified biological microparticles such as blood corpuscles or cells of biological tissues.
2. Description of the Prior Art
Selective counting of specified biological microparticles such as blood corpuscles or the cells of a biological tissue is very important for assessing the state of the biological entity, especially a diseased state. For example, inflammation or allergy can be correctly diagnosed by selectively counting neutrophils, basophils, and eosinophils among granulocytes, or by selectively counting T or B cells of lymphocytes.
Selective counting of specified blood corpuscles is performed by a medical technician who discriminates stained blood corpuscles and counts them with an eye under a microscopic observation. However, in this method, since the technician discriminates and counts the stained corpuscles one at a time, processing takes a long period of time and is very inefficient.
Another method exists which involves staining blood corpuscles to prepare a specimen. The specimen is screened on by a TV camera through a microscope. Then, the stained blood corpuscles are discriminated and counted by means of a pattern recognition technique. However, with this method, the preparation of the stained specimen is complicated and time-consuming. In addition, many errors frequently occur in stained blood corpuscle discrimination, and the stained corpuscles cannot be counted with accuracy.
According to still another recently proposed method, an antibody specific to the type of blood corpuscle to be counted is labeled with a fluorescent material. The labeled antibody is mixed with blood, and the corpuscles which are coupled with the labeled antibody are counted. However, with this method, the amount of fluorescent light emitted from blood corpuscles coupled with labeled antibodies is very small. In order to measure such weak fluorescence, an Ar laser or the like of about 1 W or more must be used as a high-intensity light source. The use of the high-intensity light source renders the apparatus bulky and expensive. Further, the measurement of the desired fluorescent light is influenced by the presence of natural fluorescent light emitted by proteins or fats floating in the blood.